Tubal pregnancy is not the only abnormal type of the pregnancy. There is another condition called as Molar pregnancy wherein the whole embryo has undergone molar changes. The product of conception looks like a bunch of grapes. In such condition, the HCG levels go on shooting up very high. Naturally, there would not be any heartbeats of foetus. However, according to your history, you had IVF. It means the embryo transfer was done after confirming that the embryo is normal. Ultrasonography may throw a light on this issue.